Chiral information harvesting in helical poly(acetylene) derivatives using oligo(<i>p</i>-phenyleneethynylene)s as spacers

Fernández, Zulema; Fernández, Berta; Quiñoá, Emilio; Riguera, Ricardo; Freire, Félix

doi:10.1039/d0sc02685a

Cited by 31 publications

(19 citation statements)

References 52 publications

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“…Only a few examples related to chiral PDPAs [72–85] are found in the literature compared to the large amount of work that has been done with PPAs [12–33, 37–51, 94–97] . This is due to the difficulty of obtaining the former polymers in the laboratory by polymerization of the corresponding diphenylacetylene monomers (DPA).…”

Section: Introductionmentioning

confidence: 99%

Dissymmetric Chiral Poly(diphenylacetylene)s: Secondary Structure Elucidation and Dynamic Luminescence

et al. 2022

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The secondary structure of a dissymmetric and chiral poly(diphenylacetylene) (PDPA) is elucidated by combining the data from NMR experiments (regioregular head to tail structure), Raman and IR studies (E configuration of the polyene double bonds), and high-resolution AFM images (helical pitch, packing angle and orientation of the external helix). As a result, an E-transoidal polyene backbone describing three coaxial helices is obtained. Theoretical electronic circular dichroism (ECD) studies of the structure show a good correspondence between experimental and theoretical data and allow one to decipher that the first Cotton band is generated by the poly(diphenylacetylene) core and not only by the polyene backbone. The dynamic behavior of poly-(S)-2 is also demonstrated by a helix inversion effect produced by conformational changes at the pendant groups when annealed in solvents with different donor abilities. This phenomenon is accompanied by an inversion of the circular polarized luminescence of the PDPA (CPL switch).

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Section: Introductionmentioning

confidence: 99%

Dissymmetric Chiral Poly(diphenylacetylene)s: Secondary Structure Elucidation and Dynamic Luminescence

et al. 2022

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“… 51 − 65 Regarding the helical sense induction mechanism, some research groups have demonstrated the efficient long-distance transmission of chiral information for poly(isocyanide)s, 66 , 67 poly(vinylterphenylene)s, 68 , 69 and poly(acetylene)s. 70 − 73 Recently, our group has reported on poly[oligo( p -phenyleneethynylene)acetylene]s (POPEPAs), a novel family of helical polymers. 74 In these polymers, even though the chiral center is placed at a remote position from the backbone, a helix induction occurs due to the chiral arrangement of the achiral spacers, which is harvested by the polyene backbone. Hence, in a first step the stereogenic centers of the monomer repeating units (mru) command the achiral rigid oligo( p -phenyleneethynylene) (OPE) spacers to arrange with a specific tilting degree (Θ), the value of which depends on the absolute configuration of the chiral center.…”

Section: Introductionmentioning

confidence: 99%

“…This dynamics revealed different communication mechanisms between components in both covalent and supramolecular copolymers. Therefore, different chiral amplification or chiral enhancement effects such as sergeants and soldiers, majority rules, chiral coalition, chiral accord, and chiral conflict have been observed. − As a consequence, the common properties presented by these polymers have allowed the development of materials combining these two structural motifs. − Regarding the helical sense induction mechanism, some research groups have demonstrated the efficient long-distance transmission of chiral information for poly(isocyanide)s, , poly(vinylterphenylene)s, , and poly(acetylene)s. − Recently, our group has reported on poly[oligo( p -phenyleneethynylene)acetylene]s (POPEPAs), a novel family of helical polymers . In these polymers, even though the chiral center is placed at a remote position from the backbone, a helix induction occurs due to the chiral arrangement of the achiral spacers, which is harvested by the polyene backbone.…”

Section: Introductionmentioning

confidence: 99%

Merging Supramolecular and Covalent Helical Polymers: Four Helices Within a Single Scaffold

Fernández

Quiñoá

et al. 2021

J. Am. Chem. Soc.

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Supramolecular and covalent polymers share multiple structural effects such as chiral amplification, helical inversion, sergeants and soldiers, or majority rules, among others. These features are related to the axial helical structure found in both types of materials, which are responsible for their properties. Herein a novel material combining information and characteristics from both fields of helical polymers, supramolecular (oligo( p -phenyleneethynylene) (OPE)) and covalent (poly(acetylene) (PA)), is presented. To achieve this goal, the poly(acetylene) must adopt a dihedral angle between conjugated double bonds (ω1) higher than 165°. In such cases, the tilting degree (Θ) between the OPE units used as pendant groups is close to 11°, like that observed in supramolecular helical arrays of these molecules. Polymerization of oligo[( p -phenyleneethynylene) n ]phenylacetylene monomers ( n = 1, 2) bearing L -decyl alaninate as the pendant group yielded the desired scaffolds. These polymers adopt a stretched and almost planar polyene helix, where the OPE units are arranged describing a helical structure. As a result, a novel multihelix material was prepared, the ECD spectra of which are dominated by the OPE axial array.

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“…First theoretical studies were carried out for monomer (S)-1. The molecule was built up using the geometry determined from X-ray studies [68] as a starting point, and the most stable conformers were obtained using the CREST program. This revealed the presence of two major conformers at room temperature that contribute significantly to the spectra.…”

Section: Supplementary Materialsmentioning

confidence: 99%

From Oligo(Phenyleneethynylene) Monomers to Supramolecular Helices: The Role of Intermolecular Interactions in Aggregation

Fernández

Quiñoá

et al. 2021

Molecules

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Supramolecular helices that arise from the self-assembly of small organic molecules via non-covalent interactions play an important role in the structure and properties of the corresponding materials. Here we study the supramolecular helical aggregation of oligo(phenyleneethynylene) monomers from a theoretical point of view, always guiding the studies with experimentally available data. In this way, by systematically increasing the number of monomer units, optimized n-mer geometries are obtained along with the corresponding absorption and circular dichroism spectra. For the geometry optimizations we use density functional theory together with the B3LYP-D3 functional and the 6–31G** basis set. For obtaining the spectra we resort to time-dependent density functional theory using the CAM-B3LYP functional and the 3–21G basis set. These combinations of density functional and basis set were selected after systematic convergence studies. The theoretical results are analyzed and compared to the experimentally available spectra, observing a good agreement.

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Chiral information harvesting in helical poly(acetylene) derivatives using oligo(p-phenyleneethynylene)s as spacers

Abstract: A chiral harvesting transmission mechanism is described in poly(acetylene)s bearing oligo(p-phenyleneethynylene)s (OPEs) used as rigid achiral spacers and derivatized with chiral pendant groups.

Cited by 31 publications

References 52 publications

Dissymmetric Chiral Poly(diphenylacetylene)s: Secondary Structure Elucidation and Dynamic Luminescence

Dissymmetric Chiral Poly(diphenylacetylene)s: Secondary Structure Elucidation and Dynamic Luminescence

Merging Supramolecular and Covalent Helical Polymers: Four Helices Within a Single Scaffold

From Oligo(Phenyleneethynylene) Monomers to Supramolecular Helices: The Role of Intermolecular Interactions in Aggregation

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